Rotate a point coordinates around another point in Python #python #graphics #math

python_math_rotate_point.py

#source: http://stackoverflow.com/questions/20023209/python-function-for-rotating-2d-objects

import math

def rotatePolygon(polygon,theta):
    """Rotates the given polygon which consists of corners represented as (x,y),
    around the ORIGIN, clock-wise, theta degrees"""
    theta = math.radians(theta)
    rotatedPolygon = []
    for corner in polygon :
        rotatedPolygon.append(( corner[0]*math.cos(theta)-corner[1]*math.sin(theta) , corner[0]*math.sin(theta)+corner[1]*math.cos(theta)) )
    return rotatedPolygon

def rotatePoint(centerPoint,point,angle):
    """Rotates a point around another centerPoint. Angle is in degrees.
    Rotation is counter-clockwise"""
    angle = math.radians(angle)
    temp_point = point[0]-centerPoint[0] , point[1]-centerPoint[1]
    temp_point = ( temp_point[0]*math.cos(angle)-temp_point[1]*math.sin(angle) , temp_point[0]*math.sin(angle)+temp_point[1]*math.cos(angle))
    temp_point = temp_point[0]+centerPoint[0] , temp_point[1]+centerPoint[1]
    return temp_point

Thanks for this, just pointing out that in most drawing frameworks (like pygame) Y-axis grows downwards so it actually rotates clockwise